From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: Faster read performance DURING (?) resync on raid10 Date: Fri, 26 Sep 2008 14:18:19 +1000 Message-ID: <18652.25227.7530.435789@notabene.brown> References: <19666016.post@talk.nabble.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from sminded on Thursday September 25 Sender: linux-raid-owner@vger.kernel.org To: sminded Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Thursday September 25, daniel.zetterman@gmail.com wrote: > > I have done some automated scripted tests with bonnie++ over RAID10 and > encryption, using different encryption cipher modes to evaluate the impact > on I/O operations. > The strange thing is that I can see a significant increase in read > performance (about 20%) when running the tests DURING the raid resync phase > directly after the raid creation as appose to running it after the resync, > or after I create the array with --assume-clean (which skips initial > resync). Sounds like the read-balancing is doing exactly the wrong thing - quite possible. What layout are you using (near, far, offset?), how many devices? NeilBrown